Modern platyrrhines live in Central and South America but it’s not entirely clear how their common ancestor got there. At the time, around 25 million years ago, the Panama land bridge that connected North and South American hadn’t formed, and the Atlantic Ocean was narrower. It’s possible that this ancient monkey rafted across from Africa. No matter how it got there, what happened next is clearer thanks to Perelman’s study.

After they reached South America, the platyrrhines diverged into three major families. The first to branch off were the pithecids, including the titis, the bald-faced uakaris (top left), the bearded sakis. Next came the atelids with their long, prehensile tails, including the howler (bottom right), spider and woolly monkeys.

Finally, the cebids. This group includes several species that have previously been classified in separate families; Perelman has decided to united them in one. They diverged in quick succession – first, the capuchins and squirrel monkeys (bottom left), and then, the marmosets, tamarins (top right) and the mysterious owl monkey.